Class ComponentColorModel

A ColorModel class that works with pixel values that
represent color and alpha information as separate samples and that
store each sample in a separate data element. This class can be
used with an arbitrary ColorSpace. The number of
color samples in the pixel values must be same as the number of
color components in the ColorSpace. There may be a
single alpha sample.

For those methods that use
a primitive array pixel representation of type transferType,
the array length is the same as the number of color and alpha samples.
Color samples are stored first in the array followed by the alpha
sample, if present. The order of the color samples is specified
by the ColorSpace. Typically, this order reflects the
name of the color space type. For example, for TYPE_RGB,
index 0 corresponds to red, index 1 to green, and index 2 to blue.

The translation from pixel sample values to color/alpha components for
display or processing purposes is based on a one-to-one correspondence of
samples to components.
Depending on the transfer type used to create an instance of
ComponentColorModel, the pixel sample values
represented by that instance may be signed or unsigned and may
be of integral type or float or double (see below for details).
The translation from sample values to normalized color/alpha components
must follow certain rules. For float and double samples, the translation
is an identity, i.e. normalized component values are equal to the
corresponding sample values. For integral samples, the translation
should be only a simple scale and offset, where the scale and offset
constants may be different for each component. The result of
applying the scale and offset constants is a set of color/alpha
component values, which are guaranteed to fall within a certain
range. Typically, the range for a color component will be the range
defined by the getMinValue and getMaxValue
methods of the ColorSpace class. The range for an
alpha component should be 0.0 to 1.0.

Instances of ComponentColorModel created with transfer types
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
and DataBuffer.TYPE_INT have pixel sample values which
are treated as unsigned integral values.
The number of bits in a color or alpha sample of a pixel value might not
be the same as the number of bits for the corresponding color or alpha
sample passed to the
ComponentColorModel(ColorSpace, int[], boolean, boolean, int, int)
constructor. In
that case, this class assumes that the least significant n bits of a sample
value hold the component value, where n is the number of significant bits
for the component passed to the constructor. It also assumes that
any higher-order bits in a sample value are zero. Thus, sample values
range from 0 to 2n - 1. This class maps these sample values
to normalized color component values such that 0 maps to the value
obtained from the ColorSpace'sgetMinValue
method for each component and 2n - 1 maps to the value
obtained from getMaxValue. To create a
ComponentColorModel with a different color sample mapping
requires subclassing this class and overriding the
getNormalizedComponents(Object, float[], int) method.
The mapping for an alpha sample always maps 0 to 0.0 and
2n - 1 to 1.0.

For instances with unsigned sample values,
the unnormalized color/alpha component representation is only
supported if two conditions hold. First, sample value value 0 must
map to normalized component value 0.0 and sample value 2n - 1
to 1.0. Second the min/max range of all color components of the
ColorSpace must be 0.0 to 1.0. In this case, the
component representation is the n least
significant bits of the corresponding sample. Thus each component is
an unsigned integral value between 0 and 2n - 1, where
n is the number of significant bits for a particular component.
If these conditions are not met, any method taking an unnormalized
component argument will throw an IllegalArgumentException.

Instances of ComponentColorModel created with transfer types
DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, and
DataBuffer.TYPE_DOUBLE have pixel sample values which
are treated as signed short, float, or double values.
Such instances do not support the unnormalized color/alpha component
representation, so any methods taking such a representation as an argument
will throw an IllegalArgumentException when called on one
of these instances. The normalized component values of instances
of this class have a range which depends on the transfer
type as follows: for float samples, the full range of the float data
type; for double samples, the full range of the float data type
(resulting from casting double to float); for short samples,
from approximately -maxVal to +maxVal, where maxVal is the per
component maximum value for the ColorSpace
(-32767 maps to -maxVal, 0 maps to 0.0, and 32767 maps
to +maxVal). A subclass may override the scaling for short sample
values to normalized component values by overriding the
getNormalizedComponents(Object, float[], int) method.
For float and double samples, the normalized component values are
taken to be equal to the corresponding sample values, and subclasses
should not attempt to add any non-identity scaling for these transfer
types.

Instances of ComponentColorModel created with transfer types
DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, and
DataBuffer.TYPE_DOUBLE
use all the bits of all sample values. Thus all color/alpha components
have 16 bits when using DataBuffer.TYPE_SHORT, 32 bits when
using DataBuffer.TYPE_FLOAT, and 64 bits when using
DataBuffer.TYPE_DOUBLE. When the
ComponentColorModel(ColorSpace, int[], boolean, boolean, int, int)
form of constructor is used with one of these transfer types, the
bits array argument is ignored.

It is possible to have color/alpha sample values
which cannot be reasonably interpreted as component values for rendering.
This can happen when ComponentColorModel is subclassed to
override the mapping of unsigned sample values to normalized color
component values or when signed sample values outside a certain range
are used. (As an example, specifying an alpha component as a signed
short value outside the range 0 to 32767, normalized range 0.0 to 1.0, can
lead to unexpected results.) It is the
responsibility of applications to appropriately scale pixel data before
rendering such that color components fall within the normalized range
of the ColorSpace (obtained using the getMinValue
and getMaxValue methods of the ColorSpace class)
and the alpha component is between 0.0 and 1.0. If color or alpha
component values fall outside these ranges, rendering results are
indeterminate.

Methods that use a single int pixel representation throw
an IllegalArgumentException, unless the number of components
for the ComponentColorModel is one and the component
value is unsigned -- in other words, a single color component using
a transfer type of DataBuffer.TYPE_BYTE,
DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT
and no alpha.

A ComponentColorModel can be used in conjunction with a
ComponentSampleModel, a BandedSampleModel,
or a PixelInterleavedSampleModel to construct a
BufferedImage.

Constructor Detail

ComponentColorModel

Constructs a ComponentColorModel from the specified
parameters. Color components will be in the specified
ColorSpace. The supported transfer types are
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT,
DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT,
and DataBuffer.TYPE_DOUBLE.
If not null, the bits array specifies the
number of significant bits per color and alpha component and its
length should be at least the number of components in the
ColorSpace if there is no alpha
information in the pixel values, or one more than this number if
there is alpha information. When the transferType is
DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT,
or DataBuffer.TYPE_DOUBLE the bits array
argument is ignored. hasAlpha indicates whether alpha
information is present. If hasAlpha is true, then
the boolean isAlphaPremultiplied
specifies how to interpret color and alpha samples in pixel values.
If the boolean is true, color samples are assumed to have been
multiplied by the alpha sample. The transparency
specifies what alpha values can be represented by this color model.
The acceptable transparency values are
OPAQUE, BITMASK or TRANSLUCENT.
The transferType is the type of primitive array used
to represent pixel values.

Parameters:

colorSpace - The ColorSpace associated
with this color model.

bits - The number of significant bits per component.
May be null, in which case all bits of all
component samples will be significant.
Ignored if transferType is one of
DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or
DataBuffer.TYPE_DOUBLE,
in which case all bits of all component
samples will be significant.

hasAlpha - If true, this color model supports alpha.

isAlphaPremultiplied - If true, alpha is premultiplied.

transparency - Specifies what alpha values can be represented
by this color model.

transferType - Specifies the type of primitive array used to
represent pixel values.

Throws:

IllegalArgumentException - If the bits array
argument is not null, its length is less than the number of
color and alpha components, and transferType is one of
DataBuffer.TYPE_BYTE,
DataBuffer.TYPE_USHORT, or
DataBuffer.TYPE_INT.

IllegalArgumentException - If transferType is not one of
DataBuffer.TYPE_BYTE,
DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT,
DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or
DataBuffer.TYPE_DOUBLE.

ComponentColorModel

Constructs a ComponentColorModel from the specified
parameters. Color components will be in the specified
ColorSpace. The supported transfer types are
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT,
DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT,
and DataBuffer.TYPE_DOUBLE. The number of significant
bits per color and alpha component will be 8, 16, 32, 16, 32, or 64,
respectively. The number of color components will be the
number of components in the ColorSpace. There will be
an alpha component if hasAlpha is true.
If hasAlpha is true, then
the boolean isAlphaPremultiplied
specifies how to interpret color and alpha samples in pixel values.
If the boolean is true, color samples are assumed to have been
multiplied by the alpha sample. The transparency
specifies what alpha values can be represented by this color model.
The acceptable transparency values are
OPAQUE, BITMASK or TRANSLUCENT.
The transferType is the type of primitive array used
to represent pixel values.

Parameters:

colorSpace - The ColorSpace associated
with this color model.

hasAlpha - If true, this color model supports alpha.

isAlphaPremultiplied - If true, alpha is premultiplied.

transparency - Specifies what alpha values can be represented
by this color model.

transferType - Specifies the type of primitive array used to
represent pixel values.

Throws:

IllegalArgumentException - If transferType is not one of
DataBuffer.TYPE_BYTE,
DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT,
DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or
DataBuffer.TYPE_DOUBLE.

Method Detail

getRed

public int getRed(int pixel)

Returns the red color component for the specified pixel, scaled
from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion
is done if necessary. The pixel value is specified as an int.
The returned value will be a non pre-multiplied value.
If the alpha is premultiplied, this method divides
it out before returning the value (if the alpha value is 0,
the red value will be 0).

getGreen

public int getGreen(int pixel)

Returns the green color component for the specified pixel, scaled
from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion
is done if necessary. The pixel value is specified as an int.
The returned value will be a non
pre-multiplied value. If the alpha is premultiplied, this method
divides it out before returning the value (if the alpha value is 0,
the green value will be 0).

getBlue

public int getBlue(int pixel)

Returns the blue color component for the specified pixel, scaled
from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion
is done if necessary. The pixel value is specified as an int.
The returned value will be a non
pre-multiplied value. If the alpha is premultiplied, this method
divides it out before returning the value (if the alpha value is 0,
the blue value will be 0).

getRGB

public int getRGB(int pixel)

Returns the color/alpha components of the pixel in the default
RGB color model format. A color conversion is done if necessary.
The returned value will be in a non pre-multiplied format. If
the alpha is premultiplied, this method divides it out of the
color components (if the alpha value is 0, the color values will be 0).

getRed

Returns the red color component for the specified pixel, scaled
from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion
is done if necessary. The pixel value is specified by an array
of data elements of type transferType passed in as an object
reference. The returned value will be a non pre-multiplied value. If the
alpha is premultiplied, this method divides it out before returning
the value (if the alpha value is 0, the red value will be 0). Since
ComponentColorModel can be subclassed, subclasses
inherit the implementation of this method and if they don't override
it then they throw an exception if they use an unsupported
transferType.

UnsupportedOperationException - If the transfer type of
this ComponentColorModel
is not one of the supported transfer types:
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

getGreen

Returns the green color component for the specified pixel, scaled
from 0 to 255 in the default RGB ColorSpace, sRGB.
A color conversion is done if necessary. The pixel value
is specified by an array of data elements of type transferType
passed in as an object reference. The returned value is a non pre-multiplied
value. If the alpha is premultiplied, this method divides it out before
returning the value (if the alpha value is 0, the green value will be 0).
Since ComponentColorModel can be subclassed,
subclasses inherit the implementation of this method and if they
don't override it then they throw an exception if they use an
unsupported transferType.

UnsupportedOperationException - If the transfer type of
this ComponentColorModel
is not one of the supported transfer types:
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

getBlue

Returns the blue color component for the specified pixel, scaled
from 0 to 255 in the default RGB ColorSpace, sRGB.
A color conversion is done if necessary. The pixel value is
specified by an array of data elements of type transferType
passed in as an object reference. The returned value is a non pre-multiplied
value. If the alpha is premultiplied, this method divides it out before
returning the value (if the alpha value is 0, the blue value will be 0).
Since ComponentColorModel can be subclassed,
subclasses inherit the implementation of this method and if they
don't override it then they throw an exception if they use an
unsupported transferType.

UnsupportedOperationException - If the transfer type of
this ComponentColorModel
is not one of the supported transfer types:
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

getAlpha

Returns the alpha component for the specified pixel, scaled from
0 to 255. The pixel value is specified by an array of data
elements of type transferType passed in as an
object reference. Since ComponentColorModel can be
subclassed, subclasses inherit the
implementation of this method and if they don't override it then
they throw an exception if they use an unsupported
transferType.

UnsupportedOperationException - If the transfer type of
this ComponentColorModel
is not one of the supported transfer types:
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

getRGB

Returns the color/alpha components for the specified pixel in the
default RGB color model format. A color conversion is done if
necessary. The pixel value is specified by an
array of data elements of type transferType passed
in as an object reference.
The returned value is in a non pre-multiplied format. If
the alpha is premultiplied, this method divides it out of the
color components (if the alpha value is 0, the color values will be 0).
Since ComponentColorModel can be subclassed,
subclasses inherit the implementation of this method and if they
don't override it then they throw an exception if they use an
unsupported transferType.

UnsupportedOperationException - If the transfer type of
this ComponentColorModel
is not one of the supported transfer types:
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

getDataElements

Returns a data element array representation of a pixel in this
ColorModel, given an integer pixel representation
in the default RGB color model.
This array can then be passed to the setDataElements
method of a WritableRaster object. If the
pixel
parameter is null, a new array is allocated. Since
ComponentColorModel can be subclassed, subclasses
inherit the implementation of this method and if they don't
override it then
they throw an exception if they use an unsupported
transferType.

UnsupportedOperationException - If the transfer type of
this ComponentColorModel
is not one of the supported transfer types:
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

getComponents

public int[] getComponents(int pixel,
int[] components,
int offset)

Returns an array of unnormalized color/alpha components given a pixel
in this ColorModel.
An IllegalArgumentException is thrown if the component value for this
ColorModel is not conveniently representable in the
unnormalized form. Color/alpha components are stored
in the components array starting at offset
(even if the array is allocated by this method).

getComponents

Returns an array of unnormalized color/alpha components given a pixel
in this ColorModel. The pixel value is specified by an
array of data elements of type transferType passed in as
an object reference.
An IllegalArgumentException is thrown if the component values for this
ColorModel are not conveniently representable in the
unnormalized form.
Color/alpha components are stored in the components array
starting at offset (even if the array is allocated by
this method). Since ComponentColorModel can be
subclassed, subclasses inherit the
implementation of this method and if they don't override it then
this method might throw an exception if they use an unsupported
transferType.

UnsupportedOperationException - in some cases iff the
transfer type of this ComponentColorModel
is not one of the following transfer types:
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
or DataBuffer.TYPE_INT.

IllegalArgumentException - If the components array is
not null and is not large enough to hold all the color and alpha
components (starting at offset), or if pixel is not large
enough to hold a pixel value for this ColorModel.

getUnnormalizedComponents

Returns an array of all of the color/alpha components in unnormalized
form, given a normalized component array. Unnormalized components
are unsigned integral values between 0 and 2n - 1, where
n is the number of bits for a particular component. Normalized
components are float values between a per component minimum and
maximum specified by the ColorSpace object for this
ColorModel. An IllegalArgumentException
will be thrown if color component values for this
ColorModel are not conveniently representable in the
unnormalized form. If the
components array is null, a new array
will be allocated. The components array will
be returned. Color/alpha components are stored in the
components array starting at offset (even
if the array is allocated by this method). An
ArrayIndexOutOfBoundsException is thrown if the
components array is not null and is not
large enough to hold all the color and alpha
components (starting at offset). An
IllegalArgumentException is thrown if the
normComponents array is not large enough to hold
all the color and alpha components starting at
normOffset.

getNormalizedComponents

Returns an array of all of the color/alpha components in normalized
form, given an unnormalized component array. Unnormalized components
are unsigned integral values between 0 and 2n - 1, where
n is the number of bits for a particular component. Normalized
components are float values between a per component minimum and
maximum specified by the ColorSpace object for this
ColorModel. An IllegalArgumentException
will be thrown if color component values for this
ColorModel are not conveniently representable in the
unnormalized form. If the
normComponents array is null, a new array
will be allocated. The normComponents array
will be returned. Color/alpha components are stored in the
normComponents array starting at
normOffset (even if the array is allocated by this
method). An ArrayIndexOutOfBoundsException is thrown
if the normComponents array is not null
and is not large enough to hold all the color and alpha components
(starting at normOffset). An
IllegalArgumentException is thrown if the
components array is not large enough to hold all the
color and alpha components starting at offset.

getDataElements

Returns a data element array representation of a pixel in this
ColorModel, given an array of unnormalized color/alpha
components. This array can then be passed to the setDataElements
method of a WritableRaster object.

obj - The object in which to store the data element array
representation of the pixel. If obj variable is null,
a new array is allocated. If obj is not null, it must
be a primitive array of type transferType. An
ArrayIndexOutOfBoundsException is thrown if
obj is not large enough to hold a pixel value
for this ColorModel. Since
ComponentColorModel can be subclassed, subclasses
inherit the implementation of this method and if they don't
override it then they throw an exception if they use an
unsupported transferType.

Returns:

The data element array representation of a pixel
in this ColorModel.

Throws:

IllegalArgumentException - If the components array
is not large enough to hold all the color and alpha components
(starting at offset).

ClassCastException - If obj is not null and is not a
primitive array of type transferType.

getDataElement

public int getDataElement(float[] normComponents,
int normOffset)

Returns a pixel value represented as an int in this
ColorModel, given an array of normalized color/alpha
components. This method will throw an
IllegalArgumentException if pixel values for this
ColorModel are not conveniently representable as a
single int. An
ArrayIndexOutOfBoundsException is thrown if the
normComponents array is not large enough to hold all the
color and alpha components (starting at normOffset).

getDataElements

Returns a data element array representation of a pixel in this
ColorModel, given an array of normalized color/alpha
components. This array can then be passed to the
setDataElements method of a WritableRaster
object. An ArrayIndexOutOfBoundsException is thrown
if the normComponents array is not large enough to hold
all the color and alpha components (starting at
normOffset). If the obj variable is
null, a new array will be allocated. If
obj is not null, it must be a primitive
array of type transferType; otherwise, a
ClassCastException is thrown. An
ArrayIndexOutOfBoundsException is thrown if
obj is not large enough to hold a pixel value for this
ColorModel.

ArrayIndexOutOfBoundsException - if
obj is not large enough to hold a pixel value
for this ColorModel or the normComponents
array is not large enough to hold all of the color and alpha
components starting at normOffset

getNormalizedComponents

Returns an array of all of the color/alpha components in normalized
form, given a pixel in this ColorModel. The pixel
value is specified by an array of data elements of type transferType
passed in as an object reference. If pixel is not a primitive array
of type transferType, a ClassCastException is thrown.
An ArrayIndexOutOfBoundsException is thrown if
pixel is not large enough to hold a pixel value for this
ColorModel.
Normalized components are float values between a per component minimum
and maximum specified by the ColorSpace object for this
ColorModel. If the
normComponents array is null, a new array
will be allocated. The normComponents array
will be returned. Color/alpha components are stored in the
normComponents array starting at
normOffset (even if the array is allocated by this
method). An ArrayIndexOutOfBoundsException is thrown
if the normComponents array is not null
and is not large enough to hold all the color and alpha components
(starting at normOffset).

This method must be overridden by a subclass if that subclass
is designed to translate pixel sample values to color component values
in a non-default way. The default translations implemented by this
class is described in the class comments. Any subclass implementing
a non-default translation must follow the constraints on allowable
translations defined there.

coerceData

Forces the raster data to match the state specified in the
isAlphaPremultiplied variable, assuming the data
is currently correctly described by this ColorModel.
It may multiply or divide the color raster data by alpha, or
do nothing if the data is in the correct state. If the data needs
to be coerced, this method also returns an instance of
this ColorModel with
the isAlphaPremultiplied flag set appropriately.
Since ColorModel can be subclassed, subclasses inherit
the implementation of this method and if they don't override it
then they throw an exception if they use an unsupported
transferType.

UnsupportedOperationException - if the transfer type of
this ComponentColorModel
is not one of the supported transfer types:
DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT,
DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT,
DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

getAlphaRaster

Returns a Raster representing the alpha channel of an image,
extracted from the input Raster.
This method assumes that Raster objects associated with
this ColorModel store the alpha band, if present, as
the last band of image data. Returns null if there is no separate spatial
alpha channel associated with this ColorModel.
This method creates a new Raster, but will share the data
array.